Lilly and alex went to a mexican restaurant. lilly paid $9 for 2 tacos and 3 enchiladas, and alex paid $12.50 for 3 tacos and 4 enchiladas. set up the
system of equations.

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?